Previously, many types of lapping machines have been used in endeavoring to provide an effective means to obtain a smooth lapped surface or to sharpen objects having a flat face. Many patents have been issued to special purpose lapping machines for specific purposes and to accelerate manufacturing processes.
The prior art listed below did not disclose patents that possess any of the novelty of the instant invention; however the following U.S. patents are considered related:
U.S. Pat. No.InventorIssue Date2,627,144RoshongFeb. 3, 19532,782,571HansonFeb. 26, 19573,004,371Layton et al.Oct. 17, 19614,502,252IwabuchiMar. 5, 19854,805,348Arai et al.Feb. 21, 19894,916,868WittstockApr. 17, 19905,099,614Arai et al.Mar. 31, 19926,511,365Terashima et al.Jan. 28, 2003
Roshong in U.S. Pat. No. 2,627,144 teaches a rotating lapping plate and means for supporting work on the flat surface of the plate. A number of conditioning rings are utilized to receive the work that revolves about its own axis while the plate revolves about the vertical axis of rotation of the lapping machine.
U.S. Pat. No. 2,782,571 issued to Hanson is for a device that has a horizontal lapping plate with wear rings on the plates surface. The invention adjusts the wear effect on the rings to maintain the flat surface of the plate, edge to edge to ensure efficiency in operation.
Layton et al. in U.S. Pat. No. 3,004,371 discloses a bench type lapping machine for lapping small runs of articles. Spent grit and lapping debris is removed from the working area of the lap plate and support of the drive is furnished as an integral part of the debris container.
Iwabuchi in U.S. Pat. No. 4,502,252 teaches a lapping apparatus where washing water is ejected on wafer carriers after polishing. The polished wafers are separated from the carrier and forced above the polishing member by a pushing ring. A sweeper directs the wafers into a line and pushes them into a cassette on one side of the table where they are immersed in a pure water tank.
Wittstock in U.S. Pat. No. 4,916,868 discloses a honing, lapping and polishing machine with an outer and inner gear member and a plurality of work piece holder discs which include external teeth. A drive assembly rotates the discs by an inner gear and stops the discs in a predetermined loading and unloading position.
U.S. Pat. No. 5,099,614 of Arai et al. is for a flat lapping machine with an ultrasonic sizing mechanism for automatically lapping the work such as a semiconductor wafer and a magnetic disk substrate.
Terashima et al in U.S. Pat. No. 6,511,365 teaches a lapping machine using abrasive grains in which the abrasive grains are easily removed. A moving member with a wiping face extends in a longitudinal direction and moves in the direction perpendicular to the wiping face. The moving member catches and removes foreign substances from the lapping plate.
For background purposes and as indicative of the art to which the invention is related reference may be made to the remaining cited patent issued to Arai et al. in U.S. Pat. No. 4,805,348.